Many systems use adaptive voltage scaling (AVS) loops to control the supply of power to components of the systems. An example AVS loop may include multiple delay cells coupled in series, where the speed of the delay cells varies based on a supply voltage. A signal can be sent through the delay cells, and the supply voltage can be adjusted until the signal reaches a first of the delay cells and not a second of the delay cells. In this way, the AVS loop can help to estimate the supply voltage necessary to achieve a desired level of performance.